It is known that various homogeneous or heterogeneous catalysts which possess acidic sites catalyze the condensation of ketones or aldehydes with aromatic compounds possessing at least one aromatic proton bonded directly to an aromatic nucleus. In this condensation, the carbon atom bearing the oxo group in the ketone or aldehyde becomes bonded to one or more aromatic nuclei. For example, the condensation of acetone with phenol produces primarily bisphenol A (2,2-(bis(4-hydroxyphenyl)propane), while the condensation of formaldehyde and toluene generates aromatic-substituted methanes.
At present, the condensation of acetone and phenol to give bisphenol A is effected industrially using homogeneous acid catalysts or heterogeneous ion exchange resin catalysts. The homogeneous process suffers from several disadvantages, including corrosion of the reactors, and both types of processes require the use of a high phenol:acetone ratio to produce an acceptably pure product. The condensation of formaldehyde and toluene, which may be used industrially in the pharmaceutical and specialty chemical industries, is conducted in an analogous manner and suffers from similar problems.
Such condensations of aldehydes or ketones with aromatic compounds have a tendency to produce complex mixtures of products because the product of the condensation is itself an aromatic compound possessing aromatic protons and can thus undergo further condensation to produce additional products. Thus, depending on the catalyst and reaction conditions employed, the initial products of the condensation can react with more of the starting materials or with themselves to form oligomeric species. In most industrial uses of such condensations it is, for economic reasons, desirable to optimize the production of only one of the numerous possible products. Thus, catalysts which selectively catalyze the formation of selected ones of the numerous possible products greatly improve the commercial use of this condensation.
Because molecular sieves can affect product distribution by shape selectivity, that is they can curtail the formation of products that do not have the proper shape to fit easily in the molecular sieve pores, they offer the opportunity to tailor the product distribution from such a condensation to maximize production of the desired products by appropriate choices of the molecular sieve catalyst and/or reaction conditions. However, the scientific literature reveals only a few attempts to use molecular sieves in the catalysis of these condensations, and as noted above the industrial uses of these condensations normally employ non-molecular sieve catalysts.
U.S. Pat. No. 3,496,239 issued Feb. 17, 1970 to Hamilton and Venuto and assigned to Mobil Oil Corporation describes the use of crystalline aluminosilicates such as faujasite, mordenite or zeolite Y as catalysts for such ketone/aldehyde and aromatic compound condensations.
U.S. Pat. No. 3,728,408 issued 17 Apr. 1973 to Tobias, U.S. Pat. No. 4,011,278 issued May 8, 1977 to Plank, Rosinski and Kerr, and U.S. Pat. No. 4,306,106 issued Dec. 15, 1981 to Kerr, Plank and Rosinski, all assigned in Mobil Oil Corporation, disclose by way of example the use of ZSM-5 type zeolites as catalysts in such condensations.
Showa Denko K.K., Japanese patent application No. 44-72013 (Publication No. 49-20565 published May 25, 1974) describes the use of zeolites modified with mercaptoamines as catalysts in such condensations.
Maruzen Oil K.K., Japanese patent application No. 55-106603 (Publication No. 57-31630 published Feb. 20, 1982) describes the preparation of bisphenol ethanes by reacting phenol with acetaldehyde or a derivative thereof in the presence of an acid catalyst and of a hydrocarbon or halogenated hydrocarbon solvent.
Matsuyama Sekiyu, Japanese patent application No. 52-19864 (Publication No. 53-116357 published Nov. 10, 1978) describes the condensation of substituted phenols with formaldehyde using as a catalyst a silica-alumina or silica-alumina-zeolite of deteriorated activity pretreated with water or steam.
It has now been discovered that certain non-zeolitic molecular sieves are useful as catalysts in these condensations.